A = [0 -3.5; 0 -3; 0 -2.5; 0 -2; 0 -1.75; 0 -1.5; 0 -1.25; 0 -1; 0 -0.875; 0 -0.75; 0 -0.625; 0 -0.5; 0 0; 
     0 0.5; 0 0.625; 0 0.75; 0 0.875; 0 1; 0 1.25; 0 1.5; 0 1.75; 0 2; 0 2.5; 0 3; 0 3.5];
axis([-3.5 3.5 -0.1 0.1]);
scatter(A(:,2),A(:,1));
figure;
C = [0 -0.375; 0 -0.25; 0 -0.125; 0 0; 0 0.125; 0 0.25; 0 0.375];
axis([-3.5 3.5 -0.1 0.1]);
hold on
scatter(A(:,2),A(:,1));
scatter(C(:,2),C(:,1));